Deep well pump for viscous oil



Nov. 30, 1965 Filed Feb. 4, 1964 W. N. SUTLIFF DEEP WELL PUMP FOR VISCOUS OIL 2 Sheets-Sheetl 2 1444)//1/5 U/FF INVENTOR.

United States Patent 3,220,354 DEEP WELL PUMP FDR VISCOUS GIL Wayne N. Sutliff, 2931 Pierce Road, Bakersfield, Calif. Filed Feb. 4, 1964, Ser. No. 342,344 Claims. (Cl. 10S-179) This invention relates to the art of oil well production and particularly to production from Wells in which the oil has a relatively high viscosity.

Increased demands for natural petroleum with a high viscosity and products derivable therefrom has recently awakened interest in improving the techniques of removing this type of oil from the ground. Various expedients have been applied to this problem without producing a satisfactory solution.

It is accordingly an object of the present invention to provide an improved pump which is particularly adapted to pump relatively viscous oil from a deep well.

One of the chief problems met with in pumping viscous petroleum from a well is the retarding of the return movement of the plunger in the pump barrel by the resistance set up in all portions of the pump by the viscous character of the production fluid. To solve this problem, heavy weights have been applied to the plunger but the effect of these weights greatly decrease where the bottom portion of a well inclines as much as 45 from Vertical, and such an angle of inclination is not at all uncommon. Another expedient widely tried has been to apply a coiled spring to the plunger which is stretched or compressed on the upstroke of the plunger, the tensioned spring thus speeding up the downstroke of the plunger. This functions regardless of the angle at which the well is slanted hut the spring can be made effective for only a relatively short stroke and the power applied varies radically from one end of the stroke to the other.

Another object of the present invention is to provide an improved deep well plunger pump incorporating means for increasing the speed of the downstroke of the plunger which is operative regardless of the slant of the well bore where the pump is located, and which is equally effective throughout the stroke, without limit as to the length of the stroke.

A still further object of the present invention is to provide such a deep well pump in which a substantial downward assist is given the pump plunger by the hydrostatic pressure in the lower end of the production fluid column so as to make this especially well adapted to operate in viscous oil having the tendency to retard the downstroke of the plunger.

The present application is the fifth in a series of applications for patent led by me each of which bears the title Deep Well Pump for Viscous Oil, these cases including co-pending applications Serial No. 267,562 (Case A) which matured into Patent No. 3,175,512; Serial No. 267,561 (Case B) which matured into Patent No. 3,143,080; Serial No. 279,197 (Case C) which matured into Patent No. 3,148,629; and Serial No. 290,507 (Case F) which matured into Patent No. 3,187,680. Of these applications, Cases A and B disclose pumps in each of which a substantial downward assist is given the pump plunger by the hydrostatic pressure in the lower end of the production fluid column. Each of these pumps is built into the lower end of the pump tubing and can only be withdrawn from the well for repair by pulling the tubing string.

Case C discloses a pump which not only avails itself of a substantial downward hydrostatic pressure for expediting the downward movement of the pump plunger but is designed for withdrawal of the pump plunger and 'travelling valve with the sucker rod string. The latter pump also automatically causes the tubing string to drain when the plunger is withdrawn from the pump.

Case F discloses a pump which is also integrally united 3,220,354 Patented Nov. 30, 1965 with the pump tubing string and employs a vacuum created on the upstroke of the plunger to assist in the downstroke of the latter.

It is still another object of the present invention to provide a deep well pump in which a substantial downward assist is given the pump plunger by the hydrostatic pressure of the production fluid column, in which a vacuum is produced on the upstroke of the plunger which assists in the downstroke thereof, in which the plunger is installed on the sucker rod string and may be withdrawn with the latter from the well, and in which means is provided for automatically draining the pump tubing string when the plunger is withdrawn from the pump.

The manner of accomplishing the foregong objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which FIG. l is a diagrammatic vertical sectional view of a preferred embodiment of the invention and shows the pump plunger approaching the lower limit of its downstroke.

FIG. 2 is a view similar to FIG. 1 showing the pump plunger approaching the upper limit of its upstroke.

FIG. 3 is an enlarged sectional view taken in the same plane as FIGS. l and 2 and illustrates the vacuum chamber escape valve of the pump shown in said views.

FIG. 4 is a vertical sectional View of a modified form of the pump of the invention with the plunger shown approaching the downward limit of its downstroke.

FIG. 5 is a view similar to FIG. 4 and illustrates said modified form of the invention with the plunger approaching the upper limit of its upstroke.

FIG. 6 is an enlarged fragmentary sectional view taken in the same plane as FIGS. 4 and 5 and illustrates the vacuum chamber liquid escape valve of the pump shown in said views.

Referring specifically to the drawings, and particularly to FIGS. 1, 2 and 3, a preferred embodiment of the invention is there illustrated which comprises a deep well pump 10 which includes a barrel 11 having upper and lower portions 12 and 13, and a plunger 14 having upper and lower portions 15 and 16.

The upper barrel portion 12 is externally threaded at its upper end and is connected by an adapter 17 to the lower end of a string of pump tubing 18. The lower end of the upper barrel portion 12 is internally threaded and screws onto matching threads provided on an adapter 19 which comprises part of the lower barrel portion 13. The balance of the lower barrel portion 13 comprises a tube 20 which is joined to the adapter 19 by threads 25 and is internally threaded at its lower end to screw onto a standing valve body 26 providing a seat 27 for a standing valve ball 28. A standing valve 29 is thus provided at the lower end of the barrel 11 which admits liquid upwardly through said valve into said barrel but traps liquid in said barrel against downward flow therefrom.

For reasons which will be made clear hereinafter, the internal diameter (ID) of the upper barrel portion 12 is slightly less than the ID of the pump tubing string 1-8 while the ID of the lower barrel portion 13 is .substantially less than that lof the upper barrel portion. An interna-l annular shoulder 30 is thus provided by the upper end of the adapter 19 where these two inside ldiameters meet.

The Lipper plunger portion 15 includes a tube 31 the upper end of which is connected by a perforated cap 32 to the lower end of a string of sucker rods 33. The upper plunger portion 15 also includes a relatively thick walled adapter 34 which connects to the lower end of tube 31 by threads 35. The lower plunger portion 16 comprises a tube which is connected at its upper end by threads 41 to the lower end of the adapter 34. At its 3 lower end tube 16 is connected by threads 42 to a travelling valve body 43 which provides a seat 44 for a ball 45, thus providing la travelling valve 46 in the lower end of plunger 14 which adm-its liquid upwardly into said plunger but prevents its escape downwardly therefrom.

The upper plunger portion 15 has an external diameter which slidably ts within the upper barrel portion 12 and the lower plunger portion 16 has an external diameter which slidably iits within the lower barrel porti-on 13. At the juncture between the external diameters f the upper and lower plunger portions and 16 an annular external shoulder 47 is provided by the adapter 34 which shoulder is disposed in axi-ally opposing relation with the internal annular shoulder 30 provided on the barrel 11.

In the operation of the pump 10, the plunger 14 is reciprocated vertically in the barrel 11 by the string of sucker rods 33 and the separation of the internal and external shoulders 30 and 47 produces a Vacuum charnber 48 within the upper barrel portion 12 and between said shoulders. A vacuum is formed in said chamber during each upstroke of the plunger 14 and this vacuum materially assists and speeds the immediately following down-stroke of said plunger. To prevent an accumulation of liquid in said vacuum chamber a liquid escape passage 49 is provided in the adapter 34. The lower end of this passage, which communicates with said vacuum chamber, has a reduced diameter to provide a valve seat 50 while the upper end of said passage is internally threaded and has screwed therein a threaded sleeve 55. Trapped within passage 49 by said sleeve are an escape valve ball 56 and a coiled spring 57 which yieldably holds said ball against said seat to provide an escape valve S8.

The escape valve ball 56 readily yields to permit the escape of liquid, which has accumulated in vacuum chamber 48, upwardly through escape passage 49 whenever plunger 14 approaches the lowermost limit of its downstroke as shown in FIG. 1, but valve 58 closes immedi- -ately at the start of the upstroke of the plunger so as to prevent any flow of liquid through said valve into said chamber. The upper end of the escape passage 49 communicates through sleeve 55 with the interior of the upper plunger portion 15 and through the perforated cap 32 with the production fluid -column contained within the pump tubing string 18.

Provided in the adapter 19 is a drain hole 59, the purpose of which will be made clear hereinafter.

Operation The installation of deep well pump 10 in a well is effected by securing the barrel 11 of said pump on the lower end of tubing string 18 and lowering the latter into a well (not shown) until said barrel is submerged in a body of oil at the bottom of the well. The upper level of this body of oil is generally located some distance above the upper end of the pump barrel 11 and the su'bmergence of the pump barrel in this oil causes it to llow upwardly through the standing valve 29 to approximately the same level the oil has outside said tubing string.

The plunger 14 is now assembled on the lowermost element of the sucker rod string 33 and the latter is assembled and inserted downwardly into the well so as to eventually lower the pump plunger 14 into the barrel 11 as this is shown in FIG. 1. Oil trapped between the plunger 14 .and the barrel 11 between the internal and external annular shoulders 30 and 47 escapes upwardly through the escape valve 58. The pump 10 is now ready for operation which is eiected by attaching the upper end of the sucker rod string 33 to a power reciprocator at the upper end of the well and operating the latter to reciprocate the plunger 14 in the barrel 11 between. a lower position substantially as shown in FIG. 1 and an upper position substantially as shown in FIG. 2.

When the pump is so actuated 4on its downstroke, oil trapped in the lower barrel portion 13 by the standing valve 29 is forced upwardly through the travelling valve 46 into the plunger 14.` On the upstroke of plunger 14 the travelling valve 46 close-s thereby sucking a fresh charge of oil from the well upwardly through the standing valve 29 into the lower barrel portion 13. The upstroke also produces a vacuum in the vacuum chamber 48 which adds to the strain on the sucker rod string 33 during the upstroke but without producing an overload on the later. During the following downstroke, this vacuum materially assists the return of the plunger 14 to its lowermost position in the barrel 11 and speeds up this return so as to increase the production of oil by pump 10 over what this would otherwise be.

Because of the pump 10 being designed particularly for use in highly viscous oil, the plunger 14 has a relatively loose slid-ing fit in the barrel 11 and there is thus a tendency of oil to gain admittance by a very slight flow between the slidably related surfaces of the barrel 11 and plunger 14, into the vacuum chamber 48. It is essential, of course, that oil thus entering this chamber be scavenged therefrom and this is accomplished, as already described, by the escape valve 58 opening as shown in FIG. 1 when the plunger 14 approaches the lowermost limit of its downstroke.

Additional aid is given in speeding up the downstroke of the plunger 14 of the pump 10 by the very substantial difference between the horizontal cross sectional area of the upper plunger portion 15 which is exposed to hydrostatic pressure from the column of production fluid contained in the pump tubing string 18 and the horizontal cross sectional area of the lower plunger portion 16. The amount of this hydrostatic assist may be measured by the number of square inches in the difference `between said cross section-al areas by the pounds per square inch of said hydrostatic pressure. With the diiference in cross sectional areas shown in the digrammatic representation of the invention in the drawings, the unbalance hydrostatic pressure applied downward upon plunger 14 is very substantial.

It is furthermore to be noted that the deep well pump 10 offers no problem to the designer to substantially ncrease the difference between the cross sectional areas of the upper and lower plunger portions 15 and 16 over that shown in FIGS. 1 and 2 as, for instance, by merely further decreasing the cross sectional area of the lower plunger portion. Such a decrease in the cross section of the lower plunger portion decreases the amount of oil pumped with each stroke of the pump 10 but it produces a disproportionate increase in the assistance given to the speed of the downstroke of the plunger by both increasing the cross sectional area of vacuum chamber 48 which area also represents the difference between the cross sectional areas of the upper and lower plunger portions 15 and 16 which means a corresponding increase both in the assist given by the vacuum and in the assist given by hydrostatic pressure to the downstroke of plunger 14.

To the advantages above described, deep well pump 10 adds that of offering the opportunity of recovering the plunger merely by withdrawal of the sucker rod string 33 from the well. This greatly decreases the cost of maintaining the pump 10 in operation as it affords the opportunity of servicing the travelling valve 46 and the escape valve 58 and refacing the external wearing surfaces of the plunger without the necessity of pulling the pump tubing string 18.

It is further to be noted that the drain hole 59 is 1ocated a suicient distance below the shoulder 30 and above the lower end of plunger 14, when, the latter is at the top of its upstroke (FIG. 2) so that this hold does not interfere with the efficient operation of said plunger. When the plunger is withdrawn from the well, however, drain hole 59 allows the fluid in the pump tubing string 18 to drain into the well outside the pump 10.

Referring now to FIGS. 4, 5 and 6, a modified form of the present invention is there illustrated as embodied in a deep well pump 60 which is like the pump 10 in all respects excepting that it does not embody a drain hole 59, nor does it embody an escape valve such as the escape valve 58 provided in adapter 34 of pump 10, but the pump 60 does have an escape valve 61 which will presently be described. For convenience, a detailed description of those parts of pump 60 which are identical with corresponding parts of deep well pump will be omitted and reference will be made to such parts of deep well pump 60 by use of the reference numerals applied to the corresponding parts of pump 10, with prime attached.

In place of an adapter 34 as above described in pump 10, pump 60 has an adapter 62 which does not have any escape valve embodied therein. In place of an adapter 19, as above described for pump 10, the pump 68 has an adapter 63 which is identical with adapter 19 excepting that it has escape valve 61 embodied therewith. This escape valve performs the function of scavenging liquid from vacuum chamber 48 of pump 60 but intsead of delivering this to the high presure body of liquid being forced upwardly from the pump 60 into its string of pump tubing 18', it delivers the liquid thus scavenged outwardly into the relatively low pressure body of liquid in which pump 60 is submerged.

Referring particularly to FIG. 6, the adapter 63 is seen to have a deep external recess 64 and the escape valve 61 is formed in said adapter between said recess and the upper end of the adapter. The valve includes a vertical bore 65 having a counterbore 70 providing a shoulder at its juncture with said hole which forms a valve seat 71. The lower end of counterbore 70 is tapped to receive a short threaded sleeve 72 which traps within said counterbore a valve ball 73 and a coiled expansion spring 74 which yieldably holds said ball against said seat.

The escape valve 61 functions, as shown in FIG. 4, to open as the plunger 14 of pump 60 approaches the lower limit of its downstroke to allow liquid trapped in the vacuum chamber 48 to escape downwardly through said valve into recess 64 which is in direct communication with the oil body in which the pump is submerged. With the conclusion of the downstroke, escape valve 61 closes, as shown in FIG. 5, so that the upstroke of plunger 14 which follows produces a Vacuum in annular vacuum chamber 48 which speeds up the rate of travel of the plunger 14 on its immediately following downstroke.

From the foregoing description of modified deep Well pump 60 shown in FIGS. 4, 5, and 6, it is believed manifest that it follows the same basic mode of operation as that of deep well pump 10, the only difference being that in pump 60, the scavenging of liquid from the vacuum chamber 48 is effected by discharging this into the oil body in which the pump is submerged whereas in pump 10 liquid scavenged from the vacuum chamber 48 is discharged into the upper end of the plunger 14 which communicates directly through the perforated cap 32 with the liquid body confined within the pump tubing string 18 which is normally referred to as the production fluid column. While the pump 10 exhibits the advantage of making it possible to service the escape valve 58 whenever the sucker rod is withdrawn from the well, this requires that the escape valve be mounted in the adapter 34 so that in order to scavenge liquid from the vacuum chamber 48, this must be raised to a pressure in excess ofthe very high hydrostatic pressure existing in the production fluid column within the lower end of the pump tubing string 18. On the other hand, while the pump 60 enjoys the advantage of the escape valve 61 being positioned to scavenge liquid from the vacuum chamber 48 by discharging this into the relatively low pressure body of oil in which the pump is submerged, this advantage is obtained at the cost of embodying said escape valve with the adapter 63 so that it is not possible to service this valve without pulling the string of pump tubing 18' on which pump 6d is suspended.

A further advantage inherent in pump 60 is found in the fact that when the plunger 14' thereof is withdrawn from the well the escape valve 61 is exposed to the production iuid column in tubing string 18' so that the fluid in this column drains outwardly through this valve into the well space surrounding said pump.

In conclusion, it is to be understood that the preferred form of the invention and only one modified form of the same are specifically disclosed herein for illustrative purposes only, and that various changes and modifications may be made in these without departing from the spirit of the invention or the scope of the appended claims.

The claims are:

1. A deep well pump associated, when in use with a production tubing string and a sucker rod string, said pump comprising: a pump barrel having means for c011- necting the upper end thereof to the lower end of said tubing string, the ID of an upper portion of said barrel being slightly less than the ID of said tubing string, said barrel having a lower portion the ID of which is substantially less than the ID of said upper portion, an annular internal shoulder being formed in said barrel at the juncture of said portions; a standing valve provided at the lower end of said lower portion of said barrel for checking downward flow therefrom; a hollow pump plunger slidable within said barrel and including upper and lower portions which respectively slidingly t said upper and lower barrel portions, an annular external shoulder being provided in said plunger at the juncture of said portions thereof, said plunger having means at its upper end for connecting the same to said sucker rod string; and a travelling valve provided on said plunger for checking downward flow through said plunger, said pump, when in operation, being submerged in a body of liquid in said well with said plunger being reciprocated to produce a pumped body of liquid in said tubing string, a vacuum being produced in the space between said two annular shoulders during each plunger upstroke which materially assists and speeds up the immediately following downstroke of said plunger.

2. A combination as recited in claim 1 wherein means is provided for causing the escape of liquid trapped between said shoulders into one of the aforesaid bodies of liquid.

3. A combination as recited in claim 2 wherein said escape means comprises checked valved passage means communicating between the space between said internal and external annular shoulders and that one of said bodies of liquid.

4. A combination as recited in claim 3 wherein said check valve passage means is provided in said upper portion of said plunger and connects with said liquid body in said tubing string.

5. A combination as recited in claim 3 wherein said check valve passage means is provided in said lower portion of said barrel and communicates with said liquid body surrounding said pump.

References Cited by the Examiner UNITED STATES PATENTS 1,545,474 7/1914 Adams 103-179 DONLEY I. STOCKING, Primary Examiner. 

1. A DEEP WELL PUMP ASSOCIATED, WHEN IN USE WITH A PRODUCTION TUBING STRING AND A SUCKER ROD STRING, SAID PUMP COMPRISING: A PUMP BARREL HAVING MEANS FOR CONNECTING THE UPPER END THEREOF TO THE LOWER END OF SAID TUBING STRING, THE ID OF AN UPPER PORTION OF SAID BARREL BEING SLIGHTLY LESS THAN THE ID OF SAID TUBING STRING, SAID BARREL HAVING A LOWER PORTION OF THE ID OF WHICH IS SUBSTANTIALLY LESS THAN THE ID OF SAID UPPER PORTION, AN ANNULAR INTERNAL SHOULDER BEING FORMED IN SAID BARREL AT THE JUNCTURE OF SAID PORTIONS; A STANDING VALVE PROVIDED AT THE LOWER END OF SAID LOWER PORTION OF SAID BARREL FOR CHECKING DOWNWARD FLOW THEREFROM; A HOLLOW PUMP PLUNGER SLIDABLE WITHIN SAID BARREL AND INCLUDING UPPER AND LOWER PORTIONS WHICH RESPECTIVELY SLIDINGLY FIT SAID UPPER AND LOWER BARREL PORTIONS, AN ANNULAR EXTERNAL SHOULDER BEING PROVIDED IN SAID PLUNGER AT THE JUNCTURE AT SAID PORTIONS THEREOF, SAID PLUNGER HAVING MEANS AT ITS UPPER END FOR CONNECTING THE SAME TO SAID SUCKER ROD STRING; AND A TRAVELLING VALVE PROVIDED ON SAID PLUNGER FOR CHECKING DOWNWARD FLOW THROUGH SAID PLUNGER, SAID PUMP, WHEN THE OPERATION, BEING SUBMERGED IN A BODY OF LIQUID IN SAID WELL WITH SAID PLUNGER BEING RECIPROCATED TO PRODUCE A PUMPED BODY OF LIQUID IN SAID TUBING STRING, A VACUUM BEING PRODUCED IN THE SPACE BETWEEN SAID TWO ANNULAR SHOULDERS DURING EACH PLUNGER UPSTROKE WHICH MATERIALLY ASSISTS AND SPEEDS UP THE IMMEDIATELY FOLOWING DOWNSTROKE OF SAID PLUNGER. 